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Oil pressure switch and light

Posted: Fri Jul 04, 2014 5:21 pm
by moomoo
Hi all,
My oil pressure light on the dash has stopped working ie there is no light on at all. There is continuity between the wire on the pressure switch and the bulb holder but there is no power to either. Does anyone know where the power source comes from to the pressure switch? The white and red wire vanishes into theloom near the starter motor. :cry: :cry:
I have the Opel 1979 petrol engine.

Thanks
moomoo

Re: Oil pressure switch and light

Posted: Fri Jul 04, 2014 5:24 pm
by moomoo
I should have said Opel 1979cc or 2.0l petrol engine.

Re: Oil pressure switch and light

Posted: Fri Jul 04, 2014 6:00 pm
by Phil Bradshaw
Wires to the warning lamp bulb holder should be white+brown and green.

White+brown goes directly to the oil pressure switch.
Green is power, from ignition supply which is the same for the alternator warning lamp so if that's working then the supply to the oil warning lamp also should be ok.
If no supply to the oil warning lamp green wire then, in the wiring behind the dash panel, look for a bullet connector* with a number of green wires to it and check each one is secure.

Switch is earth return type, the switch body being grounded through the engine.
When engine not running a multimeter should show low or no resistance between switch body and terminal.
Grounding the white+brown wire to the engine should operate the warning lamp when ignition switched on.

*EDIT
Only on Facelift models with 12-way fusebox.
Not on CF2 models with 21-way fuse box.

Re: Oil pressure switch and light

Posted: Fri Jul 04, 2014 8:00 pm
by moomoo
There is power on the green wire but oddly the bulb is an SE24v is this right?

Re: Oil pressure switch and light

Posted: Fri Jul 04, 2014 8:16 pm
by moomoo
Are the instrument panel bulbs still available.....Ive looked for the oill pressure bulb but cant seem to find them anywhere.
I bought some T4W but they are much bigger than the bulb in the instrument panel.
Any ideas?

Re: Oil pressure switch and light

Posted: Fri Jul 04, 2014 9:21 pm
by Phil Bradshaw
Warning lamp bulbs should be 12V 2W peanut, BA7s.

Re: Oil pressure switch and light

Posted: Fri Jul 04, 2014 9:45 pm
by moomoo
A veritable mine of knowledge as usual....thanks Phil....Ive ordered a couple and I'll see how it goes. :D :D :D

Re: Oil pressure switch and light

Posted: Mon Jul 07, 2014 5:09 pm
by moomoo
Hi
Ive put the new bulb into the oil pressure warning light socket ...turned on the ignition and nothing.
Ive put the voltmetrer across white and brown wire and green wire and its showing only 2 volts or thereabouts... :(
When i put the voltmeter across green and earth its showing 12.5volts
There is continuity between the white and brown wire connector at the oil pressur.e sender unit and the bulb socket holder...
Any advice would as always be gratefully welcome. 8-)

moomoo

Re: Oil pressure switch and light

Posted: Mon Jul 07, 2014 5:40 pm
by Phil Bradshaw
Disconnect white + brown wire from oil pressure switch.
Ground the wire to the engine.
If the lamp lights then the oil pressure switch is faulty.
Intermotor 50510 or equivalent for a new switch.

Re: Oil pressure switch and light

Posted: Mon Jul 07, 2014 8:10 pm
by moomoo
Hi Phil
thanks for the info....did exactly what you said and..... bingo!...it was the oil pressure switch that was faulty.....thanks again! :D :D :D